Arc discharge device



Jan. 17, 1933. F. P; WHITAKER ARC DISCHARGE DEVICE Filed March 12, 1932Invent 0P 2 Frank P. WhiLaKeP, b9

His AttoPne which may Patented Jan. 17, 1933 PATENT Fries 1P. WHITAKER,OF RUGBY, ENGLAND, ASSIGNOR TO GENERAL ELECTRIC COM PANY,

A CORPORATION OF NEW YORK ARC DISCHARGE DEVICE My invention relates toare discharge devices such as mercury arc rectifiers, more par ticularlyto the construction of the shields for the anodes of these devices, andits principal -'obje'ct is the provision of an anode shield constructionwhereby the output oi the devices is increased.

It is general practice in mercury arc rectifiers to provide each anodewith a shield, take the form of a cylinder which surrounds the anode atits upper end and which is open at its lower end so that the arc canreach the anode. It has been proposed to provide an aperture in the sideof this shield which is connected to a part of the rectifier which iseificiently cooled, so as to reduce the vapor pressure existing aroundthe anode under certain conditions.

It has been further proposed, in an anode "shield provided with oneopening for the normal arcpath between anode and cathode, to provide anadditional opening or openings at the top or in the side of the shield,near the anode active surface and not shielded therefrom by baffles, thelatter opening or openings being comparable in area with the opening forthe normal arc path. In order that the arc might prefer to follow itsnormal path under usual load conditions, the addi- "tional opening oropenings were provided with a high ratio of surface to area of openingto facilitate deionization of incoming mercury vapor.

In accordance with my present invention "I provide an anode shieldconstruction somewhat similar to the latter above described. In thepresent invention, however, the shield structure is used in conjunctionwith a special form of container. The anodes are mounted between anouter cylinder and an inner cylinder which extends a substantialdistance below the anodes. The deionizing surfaces, which may be finsforming grilles or screens protecting the opening at the top of thecylinder, divide up the greater portion of the spaces or sectorsallotted to each anode between the inside and the outside cylinders. Theusual cylindrical shields may be dispensed with, the grilles or screensthemselves Application filed. March 12, 1832, Serial No. 598,517, and inGreat Britain March 11, 1931.

being depended on to subdivide the path for the arc.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing and itsscope will be'pointed out :in

he appended claims.

Referring to the drawing, Fig. 1 is a sectional view of an arc dischargedevice in which my invention has been embodied; Fig. 2 is across-sectional view on line 2-2 of Fig. 1; Figs. 3 and 4 arecross-sectional views illustrating modifications of the invention; Fig.5-is a sectional view illustrating a further modification; and Fig. 6 isa cross-sectional view on line 66 of Fig. 5. e

In Figs. 1 and 2, the numeral 1 represents a container or tank tor arectifier containing six anodes designated by the numerals 2 to 7 Eachanode is provided with a shield 8 and with a plurality of deionizingfins or grille members 9 which divide up the space or sector, allocatedto each anode, which is between the outer cylinder and an inner cylinder10. These spaces or sectors may be divided oii from each other by meansof radial partitions 11 although in some cases these may be dispensedwith. Openings 12 are formed in the upper portion of each shield 8providing an additional path to the anode for the arc, the normal pathof which comprises the opening at the. bottom of the shield. The fins 9extend downwardly from a point above the opening or openings-12 to apoint a substantial distance below these open ings and a substantialdistance below the lower face of the anode, thus dividing up the greaterportion of the space 13 allotted to each anode.

In the modification shown in Fig. 3, while the fins 9 are connected tothe anode shield 8 as Figs. 1 and 2, the fins are of different widths inorder to divide up more completely the space allotted to the anode.

The deionizing fins may be connected to the anode shield 8 as shown inFigs. 1, 2 and 3 or they may be connected to the container 1 and innercylinder 10 as shown in Fig. 4:.

"In the form of the invention illustrated in Figs. 1 and 2 as the anodeshield 8 extends downwardly a substantial distance below the anode, theshield thus comprises a lower portion 14 below the additional arcopenings 12 and inside the lower ends of fins 9. This 5 lower portion 14of the anode shield may be omitted, however, as shown in Figs. 5 and 6.In the construction illustrated in the latter figures the shield 15 isshort, the lower ortion corresponding to portion 14 of Fig. 1

ing dispensed with, radiating fins 16 being provided which extend belowthe lower face of the anode 12 and which may be provided with extensions17 projecting inwardly below the anode.

It is preferable, in any of the modifications .of'the inventionillustrated herein, to provide the radial partitions 11 between the tank1 and inner cylinder 10 although these p la'tions are not alwaysabsolutely essential;

Ihwill be readily understood that in any of the modifications of myinvention herein described the grille or screen members may be somountedas to beat the potential of the container or tank 1, or they may be somounted-as to be insulated from the tank, for the p ose, for -'example,of connecting the gril as or screens to leads which are connected to asource of potential whereby the grille or screenstructures may beemployed as grids or control electrodes to control the starting of therectifier.

The number of screen members or fins in each case and the distancebetween these members should be so determined that arcback is prevented.

With an anode shield construction comprisin thefin or grille arrangementabove descri ed in accordance with my invention the size of therectifier maybe-reduced as compared with those'at present in use ofequal power.

It has hitherto been usual'to deionize only the space inside the anodeshield. With the construction disclosed herein each sector of the tankmay form the anode shield and each sector will be fitted with deionizingfins or grilles sothat the customary anode shield may be omitted; 1

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an arc discharge device comprising anrevacuated container and acathode and anode mounted therein, an anode screen structure-mounted insaid container adjacent the active surfaces of said anode and comprisinga pluralityof relatively closely spaced arc sub-dividing elementsextending in a direction laterally of the anode and a plurality of 'arcsub-dividing elements extending in a direction downwardly of the anode,said screen structure'providing relatively long and narrowpassagesthroughout substantially all the space surrounding the active surfacesof the anode;

screen structure providing relatively long and narrow passagesthroughoutsubstantiall all of the space surrounding the active sur aces of theanode.

3. In an arc discharge device comprising an evacuated container and acathode and anode mounted therein, an anode screen struc- :turemountedin said container comprising;

a series of relatively closely spaced ,L-shape r fin-like membersarranged edgewise to'said anode and having a leg portion positionedlongitudinally of said anode and a foot portion positioned underneathsaid anode, said screen structure providing relatively 1011 and narrowpassages throughout substantiaE ly all of the space surrounding theactive surfaces of said anode.

4. In an arc discharge device comprising an evacuated container and acathode and anode mounted therein, an anode screen structure mounted insaid contalner comprising a plurality of relatively closely spacedfin-likiamembers arranged edgewise to said anode and extending along thesides and underneath 1 said anode, said screen structure providingrelatively long and narrowpassages throughout substantially all of thespace surrounding the active surfaces of said anode.

In witness whereof, I have hereunto set my hand.

FR ANK P. WHITAKER.

